In IBS with fructose malabsorption, BDNF protein levels (1.7 ± 0.3 ng/mg vs. 1.8 ± 0.3; p = 0.904) and BDNF mRNA levels (10.8 ± 2.8 vs. 10.2 ± 4.4, p = 0.918) did not differ from IBS without fructose malabsorption. Here, BDNF is linked to irritable bowel syndrome.